Newbie Question: Infinite Museum and Forge World Augment

I'm playing my first play-through through Rogue Trader. Had my eye on it since release but never had the time. Leaning towards a "leader class" - officer into MT or GS.

How does the augment chosen on a forge world character (which gets a -5 fellowship) interact with the augment system? Is it just a slot that is fixed, or does is that choice just a starter augment now, and that character gets an extra slot throughout the game?